September of 1752 was a sad month for much of civilization. The harvests in the month were about half of those of previous years. Birth rates and marriages rates also plummeted and commerce percentages fell. The snows of winter came earlier by calendar date. What could have happened to cause this calamity?

On 29 September 1582, Philip II of Spain decreed the change from the Julian to the Gregorian calendar. This affected much of Roman Catholic Europe, as Philip was at the time ruler over Spain and Portugal as well as much of Italy. In these territories, as well as in the Polish-Lithuanian Commonwealth (ruled by Anna Jagiellon) and in the Papal States, the new calendar was implemented on the date specified by the bull, with Julian Thursday, 4 October 1582, being followed by Gregorian Friday, 15 October 1582.